1. Field of the Invention
The present disclosure relates to valves, and more particularly to hydraulic valves such as minimum pressure shut-off valves, high pressure relief valves, fluid metering valves, pressure regulating valves, and the like.
2. Description of Related Art
Hydraulic valves such as minimum pressure shut-off valves, high pressure relief valves, fluid metering valves and pressure regulating valves are used in a variety of industrial and aerospace applications. All of these valves incorporate matched diameters with metering edges. The valves have typically been optimized to be as resistant as possible over time to contamination. However, they still suffer from the pressure and fluid flow forces driving contaminates into tight clearances. When the valves are open and flowing, contaminates in the fluid stream are directed into the tight clearances by pressure gradients and fluid momentum. When the valves are closed the pressure gradient is the greatest at the metering edges. The pressure gradients drive leakage paths, which result in contaminates being driven into the clearances such as diametrical clearances. In addition, the contaminates remain in the non-flowing areas of the metering edges. Over time contaminates have been shown to bind in these zones of valves, and can eventually result in the need for maintenance and/or valve replacement.
Such conventional methods and systems have generally been considered satisfactory for their intended purposes. However, there is still a need in the art for improved valves. The present disclosure provides a solution for this need.